SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8763754dba58395f3855aa65edbcdc06abdd5908cb939d7cc9ee4066541e2f7' 
  AND token = '5Eoxa9GewxWAqMlZrVQEGClmqUgk2R7tZ029sqavvio=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}